Development Of Face

Question 1

Development of face

Answer 1

Face is formed by growth and fusion of 5 prominences around stomodeum (depression present ventrally between forebrain bulge and pericardial bulge, its floor is Buccopharyngeal membrane)

Question 2

5 prominences

Answer 2

1. Median fronto-nasal prominence
2. Two maxillary prominences
3. Two Mandibular prominences

Question 3

Median fronto-nasal prominence

Answer 3

1. Formed by mesenchyme proliferation ventral to brain vesicle
2. It grows ventral to stomodeum

Question 4

Maxillary prominence

Answer 4

1. Formed by forwards growth of 1st pharyngeal arches dorsal end
2. They grow lateral to stomodeum

Question 5

Mandibular prominences

Answer 5

1. Formed by forward growth of 1st pharyngeal arches ventral end
2. They grow caudal to stomodeum

Question 6

Differentiation and fusion: frontonasal prominence

Answer 6

1. 2 nasal placodes
2. Nasal pits
3. Lateral and medial nasal prominences (folds)
4. Maxillary prominences

Question 7

2 nasal placodes

Answer 7

1. Ectodermal thickening
2. Develop on both sides of frontonasal prominence

Question 8

Nasal pits

Answer 8

Olfactory pits
Nasal placodes are invaginated to form nasal pits

Question 9

Maxillary prominences

Answer 9

Grow medially compressing medial nasal prominences towards midline where they merge together forming intermaxillary segment which separates between maxillary prominences

Question 10

Fate (derivates) frontonasal prominence

Answer 10

1. Forehead and nose bridge
2. Lateral nasal prominence (contributes to nose ala)
3. Intermaxillary segment

Question 11

Intermaxillary segment

Answer 11

Give rise to:
1. Labial component: forming upper lip philtrum
2. Upper jaw component: carrying 4 incisor teeth
3. Palatal component: forming primary palate

Question 12

Differentiation and fusion: maxillary prominences

Answer 12

Grow and fuse with frontonasal prominence side (lateral nasal fold) and with inter maxillary segment side and fuse causally with Mandibular prominences
Give rise to:
1. Cheek upper part and lower eyelid
2. Upper lip (except philtrum)
3. Upper jaw (except median part carrying 4 incisors)
4. Secondary palate

Question 13

Nasolacrimal duct

Answer 13

1. Formed as ectodermal cells cord at fusion line between frontonasal side and maxillary prominences
2. Cord will be embedded beneath fused prominences and canalized forming Nasolacrimal duct

Question 14

Differentiation and fusion: Mandibular prominences

Answer 14

1. Fuse above with maxillary prominence forming cheek lower part
2. Fuse with each other in midline forming lower lip, lower jaw, and mouth cavity floor

Question 15

Nerve supply

Answer 15

Trigeminal nerve supplies the 5 facial prominences (ophthalmic nerve supplies frontonasal prominence, while maxillary and Mandibular nerves supply maxillary and Mandibular prominences respectively)